Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef53161bb1e31493…

MALICIOUS

PDF

74.0 KB Created: 2021-09-19 10:02:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: a20c3b5575161c82f2f2cba1e29c6355 SHA-1: 697f5fcc864eb3864b5c5551b1d14fc877e24c32 SHA-256: ef53161bb1e31493598b395556f367032050cfd4d206727ee105ef2f9ebb0f6a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs pointing to various domains, many of which are identified as link farms on disposable hosting or compromised CMS uploads. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware delivery. While no scripts were explicitly extracted, the structure suggests it could leverage PDF's scripting capabilities to redirect users.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://inwebjor.ru/uplcv?utm_term=k+4+letter+words PDF link annotation
    • http://majortaylorride.info/images/uploaded/file/gebukejepixawezudir.pdfIn PDF document text
    • https://kuzeyilac.com/resimler/files/54210114409.pdfIn PDF document text
    • https://mamap.in/ci/userfiles/files/47688379277.pdfIn PDF document text
    • http://artpolyclinic.com/file/files/98870241637.pdfIn PDF document text
    • http://ohana1bbq.com/uploads/files/nutemalilagesivufapat.pdfIn PDF document text
    • http://argra.rs/wp-content/plugins/formcraft/file-upload/server/content/files/161378241e1e41---sizarasudidewan.pdfIn PDF document text
    • http://locthanhroyal.com/upload/files/jujoneta.pdfIn PDF document text
    • http://strojsteel.cz/webpagebuilder/ckfinder/userfiles/files/58380368317.pdfIn PDF document text
    • http://bkm-market.net/userfiles/file/10902553205.pdfIn PDF document text
    • https://go2germany.ru/files/file/lutipepi.pdfIn PDF document text
    • https://www.hasmow.com.au/application/third_party/ckfinder/userfiles/files/91427299817.pdfIn PDF document text
    • http://totalfinance.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1612f2aa11d1c1---noxufugobuwulozu.pdfIn PDF document text
    • https://legacydockandmarine.com/wp-content/plugins/super-forms/uploads/php/files/aa5533baba0b4c4505cd425eeaa914da/70870731785.pdfIn PDF document text
    • http://reutlinger.pl/userfiles/file/vudalarapigasin.pdfIn PDF document text
    • http://specimport.by/files/files/dozefuduzovefisugabeludo.pdfIn PDF document text
    • https://standsimulator.com/ckfinder/userfiles/files/kawipegoramalawofe.pdfIn PDF document text
    • http://nirmalapublicschoolerumely.com/userfiles/file/jilobokivixurososif.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000be08.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBE08 10040 bytes
SHA-256: e38ed4b38a8ec152479480ca1c98413d39e035b89b2de89eaea643ba553960c3
font_01_sfnt_off0000d492.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD492 17812 bytes
SHA-256: 86a5995badca6a4bed486dba771cc4ad90e856513e5c3da93b505ca25386429d
font_02_sfnt_off000102fc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102FC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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